Process of finishing textile material



Nov. 14, 1939. H. HUEY 2,179,505

PROCESS OF FINISHING TEXTILE MATERIAL Filed A ril 12, 1957 NVENTOR dd J.

' ATTQRNEY W. M,- iese Patented PROCESS OF FINISHING TEXTILE MATERIAL Harold ll. Huey, lLincoln, R. l., assignor to Sayles Finishing Plants, llnc., Saylcsville, R. l[., a corporation oi lithode Island Application April 12, 1937, Serial No. 136,304 7 6 Claims.

The present invention relates to a process for imparting improved silk-like effects of great brilliance and lustre to cellulosic fibrous materials, such as cotton yarns and fabrics, and the products produced thereby.

It has long been a major objective in the production and finishing of cotton yarns and fabrics to be able to impart to the cotton the beauty, lustre, and feel of true silk. Thus, as a result of the Work of Mercer many years ago, the process which bears his name was developed. and has found widespread application. Asa result of mercerization cotton yarns and fabrics are improved in appearance and take on a considerably increased lustre. However, only by the use of expensive, high-grade, long staple cotton yarns of low twist, can the mercerization process produce effects which approach the beauty of silk. This limitation of the mercerization process has long been real'zed and much time and effort has been expended in attempts to improve mercerization, or to develop new processes for the production of silk-like effects on cotton. To this end chemicals having a more intense action on cellulose than caustic soda have been employed in the hope of more nearly approaching the appearance of silk. While the greater chemical attack upon the cotton fibre has in certain cases produced yarns of increased surface reflectivity and metal-like shine, this has been accompanied, invariably, by a serious stiffening of the yarns to give a harsh, coarse, disagreeable feel.

Also} it has been sought to impart the beauties of rayon to cotton yarns by covering and coating them with films of regenerated cellulose or cellulose derivatives. Such processes, however, have fallen far short of their goals in that the lustre and brilliance of rayon were not imparted to the cotton in any appreciable degree and the presence of the added coating has contributed an undesirable stiffness and boardiness, and general clumsiness .to the cotton yarns so treated.

An object of the present invention is to provide a process whereby cotton yarns and fabrics can be given a brilliant, deep-seated thread lustre similar to that of silk. A further object is to produce the just mentioned valuable properties without appreciably changing the suppleness and draping qualities of the original yarns and fabrics. A -further object is to produce a marked refinement, uniformity, sheerness and fineness in the yarns treated by the processes of the present invention. A further object is to produce these silk-like effectson types of low grade cotton yarns, such as print cloth yarns, which previously known processes have been incapable of improving. A further object is to produce yarns and fabrics having the beauty and many of the desirable qualities of silk and rayon while still preserving the durability and strength of cotton.

Heretcfore, the mercerization of cotton fabrics has generally been carried out at or below room temperatures. I have discovered however that if fabrics contain ng absorbed aqueous caustic solution are subjected for a moderateperiod of time to a controlled heating at elevated temperatures preferably while held under tension, and the caustic then washed out, the improved effects which are the objects of my invention may be accomplished without lessening the durability and strength of the cotton. Yarns and fabrics so treated are given a new beauty and refinement and possess the appearance of silk in that they become brilliant and have a deep-seated thread lustre, while the original softness, suppleness and draping qualities of the starting material are not appreciably changed.

The period of time during which I subject the impregnated fabric to elevated temperatures is preferably sufficient to produce substantially complete drying but may be sufficient to produce only partial drying. It is thus apparent that during the heating step the fabric is subjected to the action of hot aqueous caustic of increasing concentration. Hot aqueous caustic has a more intense and possibly a different reaction with the cellulose than aqueous caustic at moderate temperatures. This more intensive reaction, which is not allowed to proceed sumciently to weaken or deteriorate the yarns, is believed to account in large measure for the greatly improved effects produced. I also attribute ,the improved results in some measure to the fact that my process enables the use of a more dilute caustic solution of high penetrating power.

While it has generally been considered unsafe practice to dry or to heat cellulosic materials containing absorbed caustic soda solutions because of possible danger of oxycellulose formation and consequent tendering and weakening of the materials, I have found that such materials may be subjected to elevated temperatures according to the present invention for a sufficient period to produce the improved effects of the invention without lessening their durability and strength.

For purposes of illustration but not of limitation, the following examples of my invention are given:

Example 1.--'A bleached cotton voile is impregnated with a solution of caustic soda whose concentration at room temperature is 40 Twaddell. The goods are then squeezed between rolls until they show about gain in weight. The

goods are now heated for one to two minutes to about 250 F. while under at least warp tension. The goods are then washed while under both warp and weft tension to remove the caustic.

Example 2.A bleached cotton cloth counting 64 x 60 is impregnated with a solution of caustic soda whose concentration at room temperature is 20 Twaddell. The goods are squeezed between rolls, to about gain in weight and are then heated while under warp tension and intermittent weft tension by contact with heated cylinders until the gain in weight of the goods has been reduced to about 75% by drying. The goods are then washed while under tension to remove the caustic soda.

Example 3.An unbleached cotton cloth is impregnated with a solution of caustic soda whose concentration at room temperature is 30 Twaddell. The goods are squeezed to remove excess caustic soda solution and are then heated at 220 F. for fifteen minutes while under tension. The goods are then wetted with dilute caustic soda solution and then washed while under tension to remove the caustic soda.

Example 4.A bleached and dyed cotton fabric is treated as in Example 1.

Example 5.A bleached and printed cotton fabric is treated as in Example 2.,

It is to be understood that numerous modifications'can be made in procedure without departing from the spirit of the present invention. Thus the strength of the caustic alkali solution may be varied between considerable limits, although preferably the solution will be of a concentration of at least 20 Tw. In general the greater the temperature of heating and/or the duration of the heating period, the weaker the solution of caustic alkali which may be employed. Therefore, strengths of caustic alkali solution too low to act at ordinary temperatures may become active at the elevated temperatures of the present invention. Furthermore, within limits, the higher the temperature employed the shorter the necessary heating period and conversely the longer the heating period the lower the temperature may be. Preferably the temperature employed will be in excess of 200 F. The amount of moisture removed and the degree of drying achieved during the heating period may also be varied. In general, variations in the processes and modes of operation of the present invention will be dictated largely by the types of fabrics treated and the types of finishes desired. It is emphasized that the processes of the present invention apply not only to bleached and absorbent goods, but also to grey goods and in gen eral to fibrous cellulosic materials.

In the accompanying drawing I have illustratedan arrangement ofapparatus adapted for the practice of my invention in a continuous mercerizing process, it being understood that my invention may also be carried out with other ap-' paratus and arrangement thereofthan that selected for illustration herein.

In the drawing:

Fig. 1 is a diagrammatic representation of the impregnating and heating units, with speed con.- trol device interposed; r

'Fig. 2 represents in diagram washing and expanding units, with appropriate feeding and speed control devices.

As shown in the drawing, the fabric l is drawn through atank 2 containing the impregnating caustic solution of the desired concentration, and between adjustable rubber nip rolls 3 and 4, supported on frame 5, which squeeze out excess of caustic. The rolls 3 and 4 are adjustable to leave a predetermined amount of caustic in the fabric, preferably from 100 per cent to per cent gain in weight.

From the nip rolls 3 and 4 the impregnated fabric is drawn under a compensating roll 5 which aotuates an electric speed control I, and through expander rolls 8 onto the heating unit 9. The heating unit shown consists of two vertically arranged stacks of steam-heated drums I0 and H, supported on frames I2 and I3. Between the two sets of drums l0 and H are interposed expander rolls M to prevent excessive shrinkage of the fabric during drying. The fabric I is drawn upward over the drums l0, laterally over the expander rolls it and downwardly over the drums H. The speed at which the fabric movesthrough the heating unit 'is controlled so that any given portion of the impregnated fabric passes completely through the unit in the time predetermined as desirable for the heat treatment to endure.

From the heating unit 9 the fabric passes over and under tension bars 15, over a clock roll l6, under compensating roll ll of speed control l8 and thence through feeders l9 into pad box 20. Pad box 20 contains water or dilute caustic soda solution. The fabric is drawn into the solution at one end of box 20, out and between pressure rolls 2! and 22, back into the solution at the other end of box 20 and out between pressure rolls 22 and 23 to an expanding unit 24. In the expanding unit the fabric passes over a series of curved expander rolls 25 while being sprayed with fine streams of water and is then subjected to further washing in water in a second washing unit 25. From this latter washing unit the fabric passes out through pressure rolls 2'! and 28 to suitable drying apparatus (not shown) While I have found the above described textile finishing apparatus and arrangement thereof particularly suited to the practice of my invention, other types of finishing machinery are well known and may be adapted to the practice of my process. For example, the impregnation with caustic alkali can be carried out in a mangle, pad. or quetch. .The heating of the impregnated fabric can be accomplished by means of heated cylinders, drums, and cans, or by a hot chamber, or by the use of a heated tenter frame. When and if desired, tension may be appied to the warp and/or weft yarns of the fabric by any suitable means and at various places and times during the process, and may be either continuous or intermittent according to the nature of the fabrics and the effects desired. 7

It is not essential that all of the units be linked together in a continuous process, and the various operations may be carried out separately, provided the same sequence is maintained.

The process of the present invention may be .applied not only to bleached and absorbent goods,

but also to grey goods and in general to fibrous cellulosic materials. The fabric may, if desired. be first dyed or printed.

While caustic soda solutions produce very satisfactory effects when used in accordance with the teachings of the present invention, other caustic solutions commonly used in mercerizing and otherreagents capable of strongly swelling cellulose under the conditions of time and temperature set forth may be employed and are comprehended by and fall within the scope of this invention.

Having now described the nature of my invention and manners in which the same can be performed, what I claim is:

1. A process for imparting a silk-like finish to a cellulose fabric comprising impregnating the fabric wit a caustic soda solution having a concentration at least on the order of 20 Twaddell at room temperature, exposing the impregnated fabric while under tension to a dry heat in excess of 200 F. until substantially dry, and removing the caustic. 2. A process for imparting a silk-like finish to a cellulose fabric comprising impregnating the fabric with a caustic soda solution having a concentration at least on the order of 20 Twaddell at room temperature, exposing the impregnated fabric while under at least intermittent warp and weft tension to a dry heat in excess of 200 F. until substantially dry, and removing the caustic while the fabric is held under tension.

3. A process for imparting a silk-like finish to a cellulose fabric comprising impregnating the fabric with a caustic soda solution having aconcentration at least Twaddell at room temperature, exposing the impregnated fabric while under tension to a dry heat of at least 220 F. until said fabric is substantially dry, and removing the caustic.

4. A process for imparting a silk-like finish to a cellulose fabric comprising impregnating the fabric with a caustic soda solution having a concentration at least 30 Twaddell at room temperature, exposing the impregnated fabric while- 6. A process for imparting a silk-like finishto a cellulose fabric comprising impregnating the fabric with a caustic soda solution having a concentration at least 40 Twaddell at room temperature, exposing the impregnated fabric while under tension to a dry heat in excess of 200 F. until substantially dry and removing the caustic While the fabric is held under tension.

HAROLD 1. HUEY. 

